Colostral immunoglobulin transfer in calves. III. Amount of absorption.

Amount of colostrum fed and age at first feeding are the two major factors in determining maximum immunoglobulin concentration in serum for each immunoglobulin class in postcolostral calves. Both factors show linear response: increasing age, decreasing concentration; increasing amount fed up to 2 liters, increasing concentration. The two factors interact in a curvilinear response. Calves with initial feeding at progressively older ages need less colostrum to reach maximum absorption. Maximum absorption is represented by a progressively lower immunoglobulin concentration in serum with increasing age. Response surface contours for the maximum immunoglobulins IgG, IgM, and IgA, based on experimental data, have been included. Neither body weights of the experimental calves nor pooled colostral concentrations of immunoglobulin from pooled colostrums fed to the calves influenced maximum concentrations of immunoglobulin in serum.